I think what may be most productive is to make icons for everybody, but instead of trying to be super-unique for each, some will have overlap in what they need, and if you make *reusable* base icons, that will also make it easier for future extensions to adapt to.

Also, this site is really good for ideas: http://www.iconfinder.com and particularly good for drawing stuff like Facebook and Twitter icons from. Make sure you are using the correct and current logos (Twitter uses the bird now, not the 't').